Screw feed mechanical pencil with friction brake



Sept. 27, '1949. H. R. JocHlM 2,482,852

n SCREW FEED MECHANICAL PENCIL WITH FRICTION BRAKE Filed May s1, w45 2 shexsheet 1 Sept. 27, 1949. H. R. JQcHlM 2,482,852

SCREW FEED MECHANICAL PENCIL WITH FRIGTION BRAKE Filed May 5l, 1945 2 Sheets-Sheet 2 y l A? 5y /My Patented Sept. 27, 1949 :n

FRICTION BRAKE Helmet R. Jochim, Downers Grove, IIL, assignor to Rite-Rite Manufacturing Company, Downers Grove, Ill.

Application May 31, 194.5,`

; 11 Claims.

'f This invention relates to improvements in mechanical pencils or the like. One of the objects of the invention is to provide a rmechanical pencil having means to resist the propelling of the lead, i. e., unintentional lengthwise movement of the lead.

:Another object of the invention is to furnish a mechanical pencil in which the parts are so 1 constructed that they can be assembled by hand and be locked in an assembled relation without theuse v'of rolling mechanism, crimping mechanism or the like. v

With the foregoing` objects outlined and with other' objects in View which will appear as the vdescription proceeds, the invention consists in the lnovel features hereinafter described in detail, illustrated in th-e accompanying drawings, and more particularly pointed out in the appended claims. 'l i' 5 In .the drawings:y f fvF-ig. 1 is an enlarged longitudinal sectional View, partly in elevation, of the front end portion of a mechanical pencil` of .the type improved by the present invention. 1; i, Fig. 2 is a similar View of Jtion and illustrating anexample of the improvelments.

Fig.13 is a plan view of the channel tube of the pencil..VV Fig. 4 is a similar view ofthe at Yright angles to Fig. 3. 1

Fig. 5 is .an end view of the same. Fig. 6 is a side elevation partly in diametrical section of the spiral assembly. t Fig. 7 is a diametrical sectional .view of the lock cup.` Fig. 8 is an elevation of the same.r VFig. 9 is a diametrical sectional view ofthe springwasher. r Fig. 10 is an elevation of the washer. Fig. 11 is a side elevation of the eraser ferrule.

Fig. 12 is an end view of the same. Fig. 13 is a View similar to Fig. 2 but illustrat- 'ing a modification. Referring rst to Figs. 1 and 2, I4 designates 'a barrel provided with a bore I5 for the reception Vof the channel tube I6. As best shown in Figs. 3 to 5, inclusive, this tube may be made of rolled vsheet metal and is provided with a straight longitudinal channel or guideway- I1 at one side which is in -alignment with a protuberance I8 project- -ing from-.the diametrically opposite side. The Vprotuberance may cooperate with'a groove (not shown) fin the bore of .the barrel to prevent rota.- -tion -of the'tube about its'longitudinal axis. AThe n tube but taken the `rear end por- Serial No'. 596,823

- the barrel. Referring to Fig. 1, an externally corrugated ring 2l! may be secured by a press fit as at 2| to the opposite end of the channel tube for the purpose of securing the tube against axial movement in the barrel. A guide tip 22, bored to freely receive the plunger 23, is provided with a reduced tubular end portion 24 having a press t at 25 with the forward end portion of the channel tube. The lead which is activated by the plunger is marked 26.

Arranged within the channel tube is a spiral member 21 preferably made from metallic ribbon and forming a spiral slot 28 which cooperates with a projection 29 extending lat-erally from the -inner end ofthe plunger 23 and into the slot I1 of the channel tube. It will be obvious that if the spiral memloer'is turned about its longitudinal axis 'while' the channel tube is stationary, the projection 29 will be moved lengthwise of 'i the barrel I4 to propel or Withdraw the lead, depending on the direction of rotation.

For turning purposes, a driving ferrule 30 is secured to the rear end of the spiral member in Vany suitabl-e way. The driving ferrule may consist of a sheet metal cup provided with a reentrant annular flange 3|, embracing and secured to the spiral member, by? solder or the like. 'The ferrule is preferably formed of resilient sheet metal and its -outer rim, before the parts are assembled, is flared, as shown vin Fig. 6. Therefore, f

when an eraser or second ferrule V32 is placed Aabout the ferrule 30, there will be a pressV fit at `33 between these parts so that turningY of the reraser ferrule will effect turning of the driving Vferrule in the spiral member.

It will be noted from-Fig. 2 that the driving ferrule slidably engagesone face of the flange'IS of the 'channel tube-While the opposite face of the flange engages a Vspring washer 34, preferably of dish-'shape and having ra plane annular surface 35 at its rim portion, engaging the bottom 36 of a lock cup 31, formed of spring metal. From Fig. 7 it will be noted that the wall of the lock cup, before the parts are assembled, 4is ilared, and in assembly is turned in a direction opposite to that of the rim of the driving ferrule 36, and therefore when the eraser ferrule is placed .in position, there will be a press t 38 between the lock cup and the eraser ferrule which will cause the former to turn with the eraser ferrule when it is desired to project or withdraw the lead. l

. kIt may. also be seen from Fig; l2 that the eraser ferrule is long enough to receive an eraser at its rear end, and to sleeve over the rear end portion of the barrel, at its forward end, so that an ornamental bead 4l at the forward end of the ferrule may abut against an annular shoulder 42 at the exterior of the barrel. Due to this construction, it is unnecessary to secure the eraser ferrule toY the barrel by rolling a portion of the ferrule into an annular groove or the like, of the barrel.

Instead of making the lock cup 31 in one piece, Y

two parts may be used as illustrated in Fig; lf3, in which case the annular rim 31a of the cupis made separate from the bottom 31h, whiehf mayy provide or set up. a su-itable resistance against the turning of the spiral. member 21. In all mechanical pencils it is essential that the lead be held rigidly sor that pressure on the lead during Writing will not activate the mechanism and thereby' cause undesired backward. or forward movement. (It is: some times possible to control this by the exact dimensions of each part in the pencil, but in manycases where the maximum andmini-mum dimensional limits are` combined in interchangeable part assemblies, a looseness exfists which allows the lead to be retracted by the .extreme pressurev on the lead when the pencil is The spring washer of the preswent. invention provides a brakeror pressure reheld vertically.)

sisting meansto prevent or eliminate'unwanted mo-vementof the lead. Furthermore, most me- .chanicalpencils are tted with erasers and quite often when the eraser is being used, it will have a tendency to work the mechanism either forward or backward depending upon the motion of the Thus', thev spring washer sets up a re- Some eraser.

poses of the spring washer 34.

There are several advantages resulting from `the-use of the lock 'cup 31, as it provides a suitable bearing surface for thespring. washer' in re- "lati-o'n to the exterior of the bottom'of the cup,

and also provides a positive stop Vagainstthe head ofthe barrel Mfor assembly purposes by the inside: of the bottom of the cup. It also-supplies a suitable surface for' al press t or locking means 1to1r properly seat `the eraser ferrule, and it furnisl'iesl a bearing surface permitting the -lock cup to rotate with the` rotation of the eraser ferrule for smoothness in operating the mechanism.

The purposeV of the combined spring washer and lock cup is to permit a spiral assembly (the tra-cir on which the clutch and plunger travel) to become affixed to the lock cup by means of a driv- "the barrel which permitsY rotation, the spring washer being held in place. by the'v channel tube, permits the driving ferrule to be forced over the loclrcu-pand thereby locks the` parts together by very tight friction, by which the Whole operating mechanism becomes a complete unit.

Heretofore, various means for locking the parts together have been proposed. Frequently, a rolling method was used wherein some of the metal of the eraser ferrule was turned into a groove in the barrel but this prevented. any removal of the parts. One disadvantage ofthe rolling method is that any lack of uniformity or variation in the barrel surface at this point, coming in contact with some lack of uniformity of the eraser ferrule would cause an alternating variation between a tight and loose t so that as the user propelled theY lead, itwould bear tightly part of the turn andthen loosely during the balance of the turn,

and this wasl quite objectionable in the common use of the pencil. The eraser ferrule in the present construction bearing upon the spring metal lock cup which in turn bears against the barrel, permits the combination t to be manufacturen to closer dimensions, resulting. in far more uniform smoothness. in operation.

While'the foregoing taken inconnection: with the drawings discloses preferred embodiments', of the invention, it is apparent that changes may be made in the details disclosed-without departing fromath-e spirit of the; invention,- as expressed in the following claims.

What I claim and desire to secure by Letters Patent is: A

1. In a mechanical pencil,Y a barrel,v astationary channel tube positioned inf the barrel and projecting from one end thereof, a spiral.,mem ber rotatably mountedv in the tube, a driving ferrule fixed to the spiral member and. bearing against one end of the. channel tube;v a Iocls V1:11p mounted on said barrel7 a spring .means arranged between; the lock cupl and. the last-mentioned end portion of the channel tube, and a. second ferrule surrounding the driving ferrule and-lock cup and# frictionaily connected tof the. driving ferrule and lock cup.

' V2. Infa. mechanical pencil; a; barrel, a stationary channel tube positioned in `the barreLa spiral `memberV rotatably mounted in the tube, a driving ferrule fixed' to one end portion. of' the spiral member and bearing against one end portion of Vtlire channel tube, a lock cup mounted on. said member rotatably mounted in the tube., a driving ferrule fixed to the spiral memberand. bearing against one side of said. ange, a lock cup-mounted on said. barrel and arranged at-'the opposite side of said. ange, springA means; arranged between the lock cup andi the last-mentioned side of the ange and bearing against the cupf and flange, anda second ferrule surrounding. a portion of the barrel, the driving ferrnlerand ibck cup, and frictionally connected tothe` driving ferrule` and lock cup;

4.. Ina a mechanical pencil, a barrel, a: stationary channel" tube positioned inthe barrel and' having a ange projecting at one end thereof, a. spiral member rotatably mounted in the4 tube;V a driving'ferruiexxed'to the spiral member and bear:- ing against one sidev of the flange, a lock` cup mounted. on said barrel` and'V arrangedfatthe opposite side of the ange, spring means arranged between and bearing upon the lock cup and the flange, the driving ferrule being of cup-shape and having a rim portion projecting in a direction opposite to the rim of the lock cup, and a second ferrule surrounding the driving ferrule and lock cup and frictionally connected to the rims thereof.

5. In a mechanical pencil, a barrel, a stationary channel tube positioned in the barrel and having a flange projecting at one end thereof, a spiral member rotatably mounted in the tube, a driving ferrule xed to the spiral member and bearing against one side of the ange, a lock cup mounted on said barrel and arranged at the opposite side of the flange, a resilient washer arranged between and bearing against the lock cup and the flange, and a second ferrule surrounding a portion of the barrel, the driving ferrule and lock cup and frictionally secured to the driving ferrule and lock cup. Y

6. In a mechanical pencil, a barrel, a stationary channel tube positioned in the barrel and having a ilange projecting at one end thereof, a spiral member rotatably mounted in the tube, a driving ferrule fixed to the spiral member and bearing against one side of the ange, a lock cup mounted on said barrel, arranged at the opposite side of the ange and comprising a bottom washer and a ring-shaped rim, spring means arranged between and engaging the ange and the washer of theY lock cup and yieldingly urging them away from one another, and a second ferrule surrounding a portion of the barrel, the driving ferrule and lock cup, and frictionally secured to the driving ferrule and the ring of the lock cup.

7. A mechanical pencil as claimed in claim 1 vin which the driving ferrule includes a resilient ring normally tending to expand at one end of the rim.

8. A mechanical pencil as claimed in claim 1 in which the lock cup includes a rim of resilient material normally tending to flare toward the mouth of the cup. p

9. In a mechanical pencil, a barrel, a stationary channel tube positioned in the barrel and having a flange projecting at one end thereof, a spiral member rotatably mounted in the tube a driving' ferrule bearing against one side of the flange and having its central portion iixed to the spiral member and its outer peripheral portion formed of resilient material, a lock cup mounted on the barrel, arranged at the opposite side of the ange and having a'resilient rim, spring means arranged between and bearing against the lock cup and the flange for yieldingly urging them in opposite directions, and a second ferrule'surrounding a, portion of the barrel, the driving ierrule and lock cup, and frictionally secured to the rim of the lock cup and to the outer peripheral portion of the driving ferrule.

10. In a mechanical'pencil, a barrel, a stationary channel tube positioned in the barrel and projecting from one end thereof` a spiral member rotatably mounted in the tube, a driving ferrule Xed to the spiral member and bearing against oneend of the channel tube, spring means arranged between the rst mentioned end of the barrel andthe last mentioned end portion of the channel tube, and a second ferrule frictionally Y connected to and surrounding the driving ferrule.

11. In a mechanicalpencil of the type having a barrel, a spiral member positioned in the barrel and projecting from one end thereof for moving the lead axially, and a rotatable member xed on the projecting end of said spiral member for actuating the latter, resilient means arranged between said rotatable member and the last mentioned end of said barrel for resisting movement in one direction when pressure is exerted on the lead toward the spiral member and when pressure in the opposite direction is exerted on the rotatable member toward the spiral member.

Y HELMER'R. JOCHIM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Saunders Dec. 18, 1923 I-Iauton Nov. 29, 1938 Number 

